Methods of manufacturing low-pressure mercury vapor discharge lamps are described, for example, in U.S. Pat. Nos. 3,501,662 and 4,324,447. The techniques described in these patents and in other prior art constructions represent relatively low cost methods of producing these lamps. The methods described in U.S. Pat. No. 3,501,662 requires that apertures be formed in the sidewalls of the discharge tubes precoated with a luminescent layer followed by joining such tubes with a fused solder glass seal. This multi-step method does not readily adapt itself to automation. The method described in U.S. Pat. No. 4,324,447 requires the formation of separately blown collars on each discharge tube which are subsequently fused. This also is a multi-step method which can be practiced only with tubes having sufficient wall thickness so as to enable formation of the collars and subsequent fusing thereof. The latter method, when employed with tubes precoated with a luminescent layer can result in a weakened arc-containing channel, for example, as a result of luminescent phosphor particles embedded within the glass forming the channel.